# git rev-parse -q --verify ad910e36da4ca3a1bd436989f632d062dda0c921^{commit}
ad910e36da4ca3a1bd436989f632d062dda0c921
already have revision, skipping fetch
# git checkout -q -f -B kisskb ad910e36da4ca3a1bd436989f632d062dda0c921
# git clean -qxdf
# < git log -1
# commit ad910e36da4ca3a1bd436989f632d062dda0c921
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Sat Dec 7 10:41:17 2019 -0800
# 
#     pipe: fix poll/select race introduced by the pipe rework
#     
#     The kernel wait queues have a basic rule to them: you add yourself to
#     the wait-queue first, and then you check the things that you're going to
#     wait on.  That avoids the races with the event you're waiting for.
#     
#     The same goes for poll/select logic: the "poll_wait()" goes first, and
#     then you check the things you're polling for.
#     
#     Of course, if you use locking, the ordering doesn't matter since the
#     lock will serialize with anything that changes the state you're looking
#     at. That's not the case here, though.
#     
#     So move the poll_wait() first in pipe_poll(), before you start looking
#     at the pipe state.
#     
#     Fixes: 8cefc107ca54 ("pipe: Use head and tail pointers for the ring, not cursor and length")
#     Cc: David Howells <dhowells@redhat.com>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/mips-linux/bin/mips-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/mips-linux/bin/mips-linux-ld --version
# < git log --format=%s --max-count=1 ad910e36da4ca3a1bd436989f632d062dda0c921
# < make -s -j 32 ARCH=mips O=/kisskb/build/linus_mips-allnoconfig_mips-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/mips-linux/bin/mips-linux-  allnoconfig
# make -s -j 32 ARCH=mips O=/kisskb/build/linus_mips-allnoconfig_mips-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/mips-linux/bin/mips-linux-  
FIT description: Linux 5.4.0+
Created:         Sun Dec  8 07:16:02 2019
 Image 0 (kernel@0)
  Description:  Linux 5.4.0+
  Created:      Sun Dec  8 07:16:02 2019
  Type:         Kernel Image
  Compression:  gzip compressed
  Data Size:    663623 Bytes = 648.07 KiB = 0.63 MiB
  Architecture: MIPS
  OS:           Linux
  Load Address: 0x80100000
  Entry Point:  0x8022be60
  Hash algo:    sha1
  Hash value:   cadb0ca9d3ffa06478fb2f8cb2ed680d2dcbd19d
 Default Configuration: 'conf@default'
 Configuration 0 (conf@default)
  Description:  Generic Linux kernel
  Kernel:       kernel@0
Completed OK
# rm -rf /kisskb/build/linus_mips-allnoconfig_mips-gcc8
# Build took: 0:00:21.403697